Wireless communication devices and wireless networks have proliferated in recent years. Unfortunately, electromagnetic (EM) interference causes significant problems for such wireless devices and networks. The EM interference can arise from other communication devices even if those other devices use a different carrier frequency. For example, a cordless telephone using a first carrier frequency could generate EM interference that makes it difficult for a communication device using a second carrier frequency to maintain connection to a local area network (LAN). The EM interference might also arise from electronic devices other than communication devices. For example, operation of a microwave oven might cause EM interference to a communication device.
Determining what electronic device or devices are causing the EM interference can be challenging. One reason for the challenge is that the interfering device might only be used sporadically. Another reason is that the interfering device could be mobile. A possible technique to assist in locating interfering devices is to detect and classify potentially interfering EM radiation.
As an example, a particular wireless communication device that operates in compliance with an 802.11 protocol might be experiencing periodic problems associated with EM interference. Determining if there is EM radiation present other than 802.11 signals could help to locate the interfering device. For example, if this other EM radiation could be classified or characterized by spectral content, then it could be easier to determine what devices are causing interference. Spectral content can be determined and displayed by a spectrum analyzer, which displays signals in the frequency domain.
As a particular example, a microwave oven might have a spectral content that, in effect, fingerprints it as a microwave oven. For example, a microwave oven might have a spectral content with a particular shape that “hops” around randomly over time. If the spectral content could be displayed to a network administrator, the network administrator could determine that the interference might be due to a microwave oven and look for a microwave oven in the general region of the device experiencing EM interference. However, if the spectral content suggests that the interfering device is a cordless telephone, then the network administrator can take action based on this knowledge.
There are other reasons why it could be desirable to have knowledge of the spectral content in the vicinity of a wireless communication device. For example, there are certain frequency bands that are reserved for a special purpose, but which may be used for a general purpose providing that no device is using the band for the special purpose. To implement this protocol, there are communication regulatory requirements that require a device using the band for general purpose communication to vacate the band when used for the special device. For example, if a certain radar frequency band is being used by a first device for the special purpose, then that band must be vacated by a second device using the band for a general purpose. The second device learns about the special use by detecting frequency modulations referred to as “chirps”. Thus, detecting such chirps, which is a type of spectral content, is important for complying with regulations.
Thus, it would be desirable to provide a spectrum analysis of EM radiation in the vicinity of a wireless communication device or network.
The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, the approaches described in this section may not be prior art to the claims in this application and are not admitted to be prior art by inclusion in this section. Patent Application of Ben JONES, et al.